The Marketplace does not accept applications continuously throughout the year. There are two separate doors into coverage, and which one applies to you depends entirely on the calendar and on whether your circumstances recently changed.
Open enrollment: the yearly window
Open enrollment is the annual period when anyone can sign up or switch plans without needing a particular reason. It begins on November 1.
The date that actually matters to most people is December 15. If you want your coverage to start on January 1, you generally need to complete your application by then. Missing that date does not necessarily mean missing coverage altogether, but it does mean your coverage starts later than January.
Whether enrollment continues for some period after December 15 has been genuinely unsettled. The rules governing the outer deadline have changed more than once and have been challenged in court, so we deliberately do not quote a date we cannot stand behind. If you are anywhere near the December deadline, the sensible move is to talk to a licensed agent sooner rather than later, which is the safest approach regardless of how the outer date settles.
Special enrollment: the window a life change opens
Certain events open a sign-up window specifically for you, at any point during the year. That window usually lasts 60 days from the date of the event.
The events that open one include losing your existing health coverage, turning 26, moving, getting married, having a baby or adopting, and losing Medicaid or CHIP coverage. We cover each of those in more detail in what triggers a special enrollment period.
If one of those happened recently, or is about to happen, you may be able to enroll immediately rather than waiting for November.
Losing coverage works in both directions
This is the part people most often get wrong. If you already know your coverage is ending shortly, you do not have to wait until it has actually ended before starting the process.
Starting early is genuinely better, because it helps avoid a stretch of time where you are not covered at all. A gap in coverage is the outcome the whole system is designed to prevent, and it is entirely avoidable when you can see the change coming.
One rule that changed, and still causes confusion
Having a low income used to open a year-round sign-up window by itself. That provision ended in August 2025, and it is probably the single most widely misremembered rule in this subject.
A low income may still affect how much assistance you receive with the cost, and that part has not gone away. But a low income by itself is no longer a reason you can enroll outside the usual dates.
If neither door is currently open
If nothing has changed in your circumstances and open enrollment has not begun, the honest answer is that your next opportunity is probably the window starting November 1. That remains true unless something changes, such as losing other coverage, moving, or a change in your household.
Two things are still worth doing in the meantime. It is worth checking whether you qualify for Medicaid in your state, because that application stays open throughout the entire year rather than only during enrollment season. And it is worth leaving your details so a licensed agent can contact you closer to November, which costs nothing and commits you to nothing.
Why the dates are worth taking seriously
Enrollment windows are among the few genuinely rigid rules in health coverage. Financial assistance can be recalculated, plans can be switched during an open window, and mistakes on an application can generally be corrected. A missed enrollment window usually cannot be recovered, and the consequence is going without coverage until the following year.
That asymmetry is the reason to start earlier than feels necessary. There is very little cost to beginning a conversation early, and a substantial cost to beginning it late.
Why the December date matters more than the deadline debate
Discussion about enrollment deadlines tends to concentrate on the outer boundary, which is precisely the date we deliberately do not quote. That emphasis is misplaced for most people anyway.
December 15 determines whether coverage begins on January 1. Enrolling after that date, where still possible, generally produces coverage beginning in February instead, which leaves a month uninsured. An uninsured January is not a technicality if something happens during it.
The practical consequence is that the contested outer date is largely irrelevant to a decision made sensibly. Somebody enrolling by the middle of December never encounters the ambiguity, and somebody relying on the outer date is accepting a delayed start regardless of how the rules eventually settle.
Switching plans during open enrollment
Open enrollment is not exclusively for people without coverage. It is also the annual opportunity for anybody already enrolled to change plans, and reviewing existing coverage is genuinely worthwhile even when nothing has changed personally.
Plans change what they cover, which doctors participate in their networks, and what they charge, from one year to the next. A plan that suited somebody well in one year can be a poor fit in the following year without that person doing anything at all.
Automatic re-enrollment exists and is convenient, but it carries a genuine risk. Being moved automatically into a similar plan can mean accepting network changes or cost increases that a deliberate comparison would have identified.
Where to read next
- What triggers a special enrollment period
- Turning 26 and coming off a parent plan
- How to apply for Marketplace health insurance, step by step
Coverage rules differ from state to state, so it is worth reading the page for where you live: North Carolina, Florida, Texas, Tennessee, South Carolina, Alabama or Wisconsin.